Influence of the chelate effect on the electronic structure of one-electron oxidized group 10 metal(ii)-(disalicylidene)diamine complexes
Bibliographic record
Abstract
The neutral and one-electron oxidized group 10 metal, Ni(II), Pd(II) and Pt(II), six-membered chelate Salpn (Salpn = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,3-propanediamine) complexes have been investigated and compared to the five-membered chelate Salen (N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethanediamine) and Salcn (N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) complexes. Reaction of the Salpn complexes with 1 equivalent of AgSbF(6) affords the oxidized complexes which exist as ligand radical species in solution and in the solid state. The solid state structures of the oxidized complexes have been determined by X-ray crystal structure analysis. While the Ni and Pt analogues exhibit an essentially symmetric coordination sphere contraction upon oxidation, the oxidized Pd derivative exhibits an asymmetric metal binding environment demonstrating at least partial ligand radical localization. In comparison to the oxidized Salen and Salcn complexes, the propyl backbone of the Salpn complexes leads to a larger deviation from a planar geometry in the solid state. The electronic structure of the oxidized Salpn complexes was further probed by UV-vis-NIR measurements, electrochemistry, EPR spectroscopy, and theoretical calculations. The intense NIR band for the one-electron oxidized Salpn complexes shifts to lower energy in comparison to the 5-membered chelate analogues, which is attributed to lower metal d(xz) character in the β-LUMO for the Salpn series. The reactivity of the one-electron oxidized Salpn complexes with exogenous ligands was also studied. In the presence of pyridine, the oxidized Ni analogue exhibits a shift in the locus of oxidation to a Ni(III) species. The oxidized PtSalpn complex rapidly decomposes in the presence of pyridine, even at low temperature. Interestingly, electronic and EPR spectroscopy suggests that the addition of pyridine to the oxidized Pd analogue results in initial dissociation of the phenoxyl radical ligand, likely due to the increased flexibility of the propyl backbone.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".